Heat exchanger



p 1, 1953 L. H. FRITZBERG 2,650,799

HEAT EXCHANGER Filed Aug. 11, 1950 JI ZE TOR.

Patented Sept. 1, 1 953 HEAT EXCHAN GER Lawrence H. Fritzberg, Syracuse, N. Y., assignor to Aerofin Corporation, Syracuse, N. Y., a corporation of New Jersey Application August 11, 1950, Serial No. 178,785

2 Claims. 1

This invention relates to heating apparatus adapted to be installed in duct-work comprising a part of an air conditioning or heating system and, more particularly, to a device for heating air or similar fluid by heat exchange relation with steam in which the supply of steam or other heating fluid may be reduced while assuring substan tially uniform heating of the air.

The chief object of the present invention is to provide heating apparatus having a plurality of heat exchange tubes, each tube containing distributing tubes so arranged as to permit more uniform distribution of heating fluid under conditions of throttled flow of heating fluid.

An object of the present invention is to provide heating apparatus in which each heat exchange tube contains at least two distributing tubes, one of the distributing tubes having spaced orifices throughout at least a portion thereof and an open end for passage of heating fluid into the heat exchange tube, the other tube having an open end for passage of heating fluid into the heat exchange tube. Other objects of my invention will be readily perceived from the following description.

This invention relates to heating apparatus for heating air or other gaseous fluid which comprises in combination a plurality of return tubes extending across the path of air through the apparatus, a supply header, means for supplying heating fluid to the supply header, a return header connected to the tubes for removing condensate, each return tube containing a plurality of distributing tubes connected to the supply header, one of the distributing tubes having orifices therein spaced longitudinally throughout at least a portion thereof and an open end for passage of heating fluid into the return tube, another distributing tube in the return tube having an open end and being free from orifices throughout at least that portion adjacent the supply header to direct heating fluid to the opposite end of the return tube thereby assuring more uniform distribution of heating fluid throughout the return tube under conditions of throttled flow of heating fluid.

The attached drawing illustrates a preferred embodiment of my invention, in which Figure 1 is a View partly in elevation and partly in section of a heating apparatus embodying the invention; and

Figure 2 is a view similar to Figure 1 of a modification of the invention,

Referring to the drawing, there is shown heating apparatus comprising a rectangular casing structure 2 including a top wall 3, end walls 4 and a bottom wallv 5. Preferably, the casing is designed for placement in an air duct or the like so that the top and bottom walls are substantially horizontal, air flowing in a desired path through the casing.

A header structure 6 is mounted Within the casing adjacent an end wall 4. Structure 6 includes a partition I separating the structure into a supply header 8 having steam inlet 9 and a return header Ii] for removal of condensate. Outlet II of the return header I0 is placed below supply header 8 and may be connected to a drain or boiler return for disposal of condensate.

A plurality of tubes I2 extend across the path of air through the apparatus and are connected to the return header I0, each tube I2 bein closed at its end opposite its connection to the header I 0 by a plug I3 or other means. Each tube I2 may be provided with fins M if desired to promote heat transfer.

Each tube I2 contains at least two distributing tubes I5, I6 extending from supply header 8 longitudinally of tube I0 and placed one above the other. Tubes I5, I6 may be held in spaced relation to each other and to tube I2 by any desired means. Preferably, tubes I2 are disposed approximately horizontally above each other but are inclined downwardly toward the return header I0 to permit gravity flow of condensate toward the outlet I I.

Tube I5 extends approximately half-way across the air passage (refer to Figure l) and is provided with orifices I1 spaced longitudinally thereof and an open end I8 to permit heating fluid to enter the annular spaces between such tube and tube I2. It will be understood open end I8 need not be provided in tube I5 under some conditions of use. Tube I6 extends substantially throughout the length of tube I2 and is placed above tube I5 within tube I2. Tube It has an open end I9 and a plurality of spaced orifices I! extending longitudinally thereof in that portion of tube I6 extending beyond tube I5 to permit heating fluid to enter the annular space between such tube and tube I2. Thus, tubes I5, it each feed approximately one-half the length of tube I2. Under conditions of throttled steam flow, the load is divided more uniformly between the tubes I5, I6 thus utilizing their greatest heating capacity and heating air passing through the apparatus more uniformly. Under extreme throttled steam conditions, tube I6 may freeze along the portion thereof without orifices but only tube l were used. Tube l5 tends to prevent tube l6 from freezing under extremethrottled steam conditions and assures thawing thereof if freezing occurs. The construction-also im'-' proves purging of air from tube I2. uhdersbme circumstances, of course, orifices may be providedin tube l8 if desired. k p

The present invention provides a heating apparatus which assures more uniform heating 0'! air passing therethrough even under conditions of throttled steam flow. The-structure providedtends to prevent freezing of a distributing tube andassures thawing thereof-if freezing inadvertently occurs. without substantial increase in cost.

While I have described a preferred embodiment of my invention; it will be understood my invention is not limited thereto since it may beother wise embodied withinthe scope of the following claims.

I claim:

1. In heating apparatus for heating air or other gaseous fluid, the combinationof a plu'-- rality of return tubes extending across the path of air through the" apparatus, a supply header, means for supplying heating fluid to thesupply header, a return headerconnected to the tubes for removing condensate, each return tube con-- taining two distributing tubes connected to thesupply header and extending longitudinally Such advantages are providedthereof, one distributing tube having spaced orifices throughout its length and having an open end for passage of heating fluid into the return tube, the second distributing tube being free of orifices throughout its length and having an open end for passage of heating fluid into the return tube, said second distributing tube being placed above said' first distributing. tube within the return tube.

2. In heating apparatus for heating air and other gaseous fluid, the combination of a plurality of; finned return tubes extending across the path of air through the apparatus, a supply header, means for supplying heating fluid to the supply headen. a return header connected to the tubesfor"removing'condensate, the return header being placed adjacent the supply header and having its outlet placed below the supply header, the

return" tubes being inclined at an angle toward the return header to promote gravity flow 01 conderisate to the return header; each return tube containing two distributing tubes connected; to the supply header which extend longitudinally of the return tube and are inclined at a. similar angle, one distributing tube having spaced ori'-' fices throngh'o'ut its length, the seconddistributing tube being free of orifices throughout its length and having an open end for passage oi! heating fluid into the return tube;- said second distributing tube being placed: abovesaid first di's trlbutingtube within thereturn tuber LAWRENCE H.

References Cited the file of this patent UNITED STATES PATENTS Number Name Date 2,098,830 McElgin Nov. 9, 1-937 2,229,032 Ashley -a Jan. 21-, 1941 

